Physical mechanism of buffer-related current transients and current slump in AlGaN/GaN high electron mobility transistors

Kazushige Horio, Atsushi Nakajima

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

Two-dimensional transient analyses of AlGaN/GaN high electron mobility transistors (HEMTs) are performed in which a deep donor and a deep acceptor are considered in a buffer layer. Quasi-pulsed current-voltage (I-V) curves are derived from the transient characteristics. When the drain voltage is raised abruptly, electrons are injected into the buffer layer and captured by deep donors, and when it is lowered abruptly, the drain currents remain at low values for some periods and begin to increase slowly as the deep donors begin to emit electrons, showing drain-lag behavior. The gate lag could also occur due to deep levels in the buffer layer, and it is correlated with relatively high source access resistance in AlGaN/GaN HEMTs. It is shown that the current slump is more pronounced when the deep-acceptor density in the buffer layer is higher and when an off-state drain voltage is higher, because the trapping effects become more significant. The drain lag could be a major cause of current slump in the case of higher off-state drain voltage. It is suggested that to minimize current slump in AlGaN/GaN HEMTs, an acceptor density in the buffer layer should be made low, although there may be a trade-off relationship between reducing current slump and obtaining sharp current cutoff.

Original languageEnglish
Pages (from-to)3428-3433
Number of pages6
JournalJapanese Journal of Applied Physics
Volume47
Issue number5 PART 1
DOIs
Publication statusPublished - 2008 May 16

Keywords

  • Current slump
  • Drain lag
  • GaN
  • Gate lag
  • HEMT
  • Trap
  • Two-dimensional analysis

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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